In this project we seek to define and classify hereditary tumors of the nervous system; to add to the clinical description and natural history of these disease; to suggest methods for early diagnosis; to evaluate present modes of treatment; and to develop methods for preclinical detection and screening. Our studies have led to the recognition of at least two distinct genetic forms of neurofibromatosis: 1) the classical form as described by von Recklinghausen, and 2) a form in which bilateral acoustic neuromas are the hallmark. We have focused on neurofibromatosis with bilateral acoustic neuroma. Efforts have been directed at improving and simplifying screening of high-risk individuals confirming diagnosis and establishing criteria for intervention. Audiologic studies, including evaluation of auditory-evoked response and acoustic reflex decay, are a useful means for early documentation of acoustic neuroma and for following their effects. In our first major study involving neurofibromatosis of the von Recklinghausen type, a multidisciplinary program is being prepared to evaluate specific neurologic and cognitive status in a series of these patients and their first degree relatives.